Macedonian cavalry vs infantry

[Bryan]

While I appreciate the good discussion, my question was more to do with Companion cavalry in Alexander's day fighting against infantry or cavalry of the Persian Empire.

Much of actual Persian cavalry was just as heavily armored as Macedonian type, their lances were just a bit shorter though so there would be that advantage. Persian infantry were spearbearers with body length wicker shields that were not very strong, but which a spear could easily become trapped in them. Archers used spearbearers in the front rank as a provisional human pavise, their arrows could have done some significant damage to cavalry, especially horses, but with a disciplined charge at a quick pace they would have little time to loose more than a few volleys before contact. At Granicus Alexander's cavalry frontally broke through Persian cavalry and routed them and then flanked the Greek mercenary hoplites. At Issus and Gaugamela Alexander attacked the center of the Persian infantry, where Darius withdrew in panic causing a complete rout of the infantry near him that usually spread through the whole battle line that was uncommitted.